Evaluation of physiologic change in the trauma patient depends heavily upon intrusive techniques such as chronically placed catheters, magnetic flow probes, radioisotope injection, and dye dilution methods. Variables typically monitored in intensive care units are blood pressure, pulse, EKG and temperature. While considerable attention has been given to impedance and ultrasonic methods for noninvasive clinical determination of circulatory function, little work has been done to translate commercially used nuclear magnetic resonance flowmeter principles for biological investigation. This study is directed to the design of cylindrical nuclear magnetic resonance systems for monitoring blood flow in the limbs of trauma patients. Similar systems are being investigated for monitoring blood flow in the aorta, vena cava, liver and kidney. Preliminary studies in the isolated perfused kidney of the dog show that regional blood flow measurements can be made with nuclear magnetic resonance techniques. Nuclear magnetic resonance blood flow signals have been obtained from the arms of 25 volunteers and from the isolated femoral artery of the dog. Single coil systems have been capable of measuring carotid artery flow in the human, and preliminary cardiac output signals have been obtained. When the 12.5cm internal diameter lumen system is finalized, it will be integrated into our computerized monitoring system for the non-invasive evaluation of trauma patients. BIBLIOGRAPHIC REFERENCES: Ackmann, J.J., Barr, R.E., Larson, S.J., Sances, A., Jr., Hemmy, D.C., and Cuick, J.F.: Automated monitoring of evoked potentials and EEG in head injury. Proc 28th Ann Conf Eng Med Biol, 17:519, Sept. 1975. Sances, A.,Jr., Ackmann, J.J., Evans, S.M., Larson, S.J.: Application of impedance measuring techniques in the trauma patient. 2nd Int't Conf Bioelectric Impedance, Lyon, France, June 16-19, 1976.